JP2015534285A - Bonding bare chip dies - Google Patents

Abstract

A method of assembling microelectronic components is provided, the method comprising a conductive thermosetting resin material or flux base solder, and a dynamic release layer adjacent to a conductive thermoplastic material die-bonding material layer. Providing a conductive die bonding material; activating the dynamic release layer to move the conductive die bonding material material to the pad structure to be treated; and a selected portion of the pad structure is Applying a laser beam onto the dynamic emission layer adjacent to the die bonding material layer so as to be covered with the transferred conductive die bonding material, the laser beam comprising a die bonding material Timing and energy are limited so that the material remains thermoset. This allows the adhesive material to be transferred while preventing the adhesive from defeating due to excessive heat exposure during the transfer process. [Selection] Figure 2A

Description

  The present invention relates to a method for interconnecting and securing bare die chip components on a substrate, in particular on a flexible substrate.

The interconnection of individual bare chip components or microelectronic components (chips) on the substrate is a fine electrical connection so that all electrical connections and fixation to the substrate can be made when the chip component is installed in place. Or it is a process that requires accurate material deposition with sufficient accuracy to allow other types of interconnections. Typically, this process is performed by bonding with an isotropic conductive adhesive or solder paste with the bare die facing down, i.e., using the chip or bottom electrode of the package facing the circuit board electrode. It is foreseen. An example of the conductive adhesive is a temperature or UV curable resin containing silver particles. The solder paste usually contains solder particles and a flux. Such a solder paste requires a flux in order to remove the oxide layer on the particles and improve the wettability during the reflow process. Both types of interconnections, i.e., conductive adhesive and solder paste, are sensitive to thermal shock and must be avoided before mounting the chip. The flux is activated at a temperature exceeding 120 to 150 ° C., and for the conductive adhesive, thermal shock deteriorates the adhesiveness of the adhesive. In recent years, several methods for printing conductive adhesives and solder pastes for bonding bare silicon or LED chips, interposers or ball grid arrays on flexible substrates are known. Current methods include screen printing and stencil printing. Current techniques are efficient. However, these have some inherent disadvantages.
a) Screen and stencil printing are fast techniques, but they do not have the necessary resolution (about 100 um). Misalignment is likely to occur due to the contact mode and movement of the substrate web. Since these are contact mode processes, damage to the fragile substrate can occur and only a single layer of material can be deposited prior to chip mounting. The technique cannot handle non-planar surfaces and cannot compensate for web deformation, especially for foil-based roll-to-roll processes. Furthermore, the production of the screen is expensive and not very flexible, and these must be replaced after 10,000 to 100,000 operations for screen printing and 200,000 operations for stencil printing. . Finally, regular cleaning and maintenance is essential to get the right results.
b) The dispensing and jet methods are non-contact methods and do not require a stencil or mask. However, the resolution of these schemes is limited to 250 um, which is insufficient for most bare die Si chips and small passive components. Furthermore, these are relatively slow processes with a typical throughput of 10 dots per second.
c) Pin transfer is a promising method, but there are limitations on the viscosity range and thickness of the transferred layer, and the transferred shape is not flexible.

  Pique et al., “Three-Dimensional Printing of Interconnecting by Laser Direct- Write of Silver Nanopaths, Advanced Materials, Advanced Materials, by Laser Direct Depiction of Silver Nano-Pastes”. October 25, 2010, Vol. 22, No. 40, pages 4462-4466, Solvent-based dry nanosilva paste to provide another method of electrical wire bonding interconnection to bare die LEDs A laser direct writing method for transferring a film to a substrate is described. However, this method is not a reverse bonding method, and the electrical connection between the chip and the substrate is in the same direction, which does not provide any fixation by adhesion to the substrate. This is inadequate because it provides only electrical connections and no structural bonding after placing the bare die in a pocket on the polyimide substrate. In addition, this method is not suitable for most interconnect materials such as thermoset conductive adhesives, as the use of laser pulses results in the adhesive being cured or degraded to a state unsuitable for bonding.

Prior art assemblies have failed to provide an adequate method for high resolution bonding of fine pitch bare dies on flexible substrates with sufficient flexibility and reliability. The present invention seeks a solution to this problem. For this purpose, a connection pad structure arranged to interconnect a microelectronic component having one or more electrical connection pads, in particular a bare die component, to the microelectronic component via one or more connection pads, respectively. Proposed to provide a method of bonding on a substrate having a body on the substrate surface,
Providing a donor film comprising a curable conductive adhesive or flux base solder paste bonding material and a dynamic release layer adjacent to the bonding material layer;
-Aligning the laser beam of the laser system and guiding the donor film at a distance from the substrate surface;
-Actuate the laser beam on the dynamic emission layer so that the active emission layer is activated and a selected portion of the connection pad or connection pad structure is covered by the bonding material transferred from the bonding material layer; Step to
The pad of the microelectronic component is placed on the pad structure such that bonding material on one or both of the pad of the microelectronic component and the substrate pad structure forms an electrical connection between the pad structure and the respective pad. The steps addressed to
Bonding the microelectronic component with a shear strength greater than 1 Mpa by curing the conductive adhesive of the bonding material or reflowing the solder paste;
including.

  In response to the above, another bonding method is provided, in which the bonding material can be transferred with the desired resolution size, while at the same time preventing the bonding material from being invalidated by excessive heat exposure during the transfer process. it can. This bonding material can be formed by a thermosetting or thermoplastic adhesive, or a flux that includes a solder paste, in transferring the flux including the solder paste from the die bonding material to the substrate surface. The laser beam is limited in timing and energy so that the flux in the transferred bonding material remains intact. Of course, if the bonding material maintains its bonding characteristics, the bonding material remains in its original state after the bonding material is transferred from the bonding material layer to the pad or pad structure of the microelectronic component. That is, the bonding material remains suitable for the immobilization step, i.e., bonding by thermosetting material curing or solder paste reflow. Thus, an efficient bonding method is provided, in which a conventional electronic pad is positioned by positioning a microelectronic component relative to a microfeature placed on a flexible substrate. The microelectronic component pads can be bonded and electrically interconnected with a spot size with a resolution much smaller than the size.

1 shows a schematic assembly method of a microelectronic component. Figure 3 shows a schematic embodiment of a setup for transferring an adhesive or solder material. Figure 3 shows a schematic embodiment of a setup for transferring an adhesive or solder material. 1 shows a tape-based supply system for implementing a bonding method. 1 shows a tape-based supply system for implementing a bonding method. 1 shows a roll-to-roll supply system for chip assembly. Fig. 3 shows a schematic embodiment for interconnecting a ball grid array type structure to a substrate. Fig. 4 shows a schematic embodiment for the interconnection of passive components or bare dies on a foil. An example of a structured donor film is shown.

  In one aspect, a direct writing method is provided for high-speed positioning of materials that die-bond individual chip components onto a substrate, which can be operated on a reel-to-reel manufacturing scheme. Specifically, the method can be used for high resolution deposition of high viscosity materials. With the resolution achievable with the disclosed method and system, it is possible to obtain a resolution spot size for the transferred die-bonding material where the transferred bonding material has a spot diameter of less than 50 microns.

  FIG. 1 outlines several embodiments (A, B, C) of a method for bonding individual pads 30 of a bare die chip component (chip) 10 onto a pad structure 40 of a flexible substrate 20. Indicate. As described further below, the method has sufficient accuracy to correct for deformation of the web of flexible substrate 20. As used herein, the term “flexible substrate” specifically refers to a substrate that is sufficiently bendable for use in a reel-to-reel process. In other words, the flexible substrate used in this description refers to a certain curvature, for example (depending on the reel diameter), a radius of curvature of 1 to 100 centimeters, without the substrate losing its basic functionality. The substrate is flexible enough to allow bending beyond the range. The supply of chip bonding material 50 can be placed on the pad structure 40 (A in FIG. 1) or on the pad 30 of the chip, for example as shown in FIG. 1B. The chip 10 may then be bonded directly to the web pad structure 40 of the substrate 20. In addition to or instead of the above, a synthetic pattern of the conductive die bonding material and the structural adhesive 60 can be provided (C in FIG. 1). Alternatively, the present method can also be provided for interconnect pad structures disposed on a laminated flexible substrate.

2A and 2B illustrate, for the method claimed herein, die bonding material 1511 can be applied to pad structure 40 on substrate 20 (FIG. 2A) or pad 30 of bare die 10 (FIG. 2B). Fig. 2 shows an exemplary transcription setup for transcription. In an embodiment, a connection arranged to interconnect a microelectronic component having one or more electrical connection pads, in particular a bare die component 10, to the microelectronic component via each one or more connection pads. A method of bonding on a substrate 20 having a pad structure 40 on a substrate surface is provided, the method comprising:
Providing a donor film comprising a curable conductive adhesive 151 and a dynamic release layer 152;
-Aligning the laser beam of the laser system and guiding the donor film at a distance from the substrate surface;
A laser beam is applied over the dynamic emission layer such that the active emission layer is activated and the adhesive pad 50 transferred from the donor film covers a selected portion of the connection pad or connection pad structure. An actuating step wherein the laser beam is limited in timing and energy so that the transferred adhesive remains curable; and
The pad of the microelectronic component 10 is connected to the pad structure such that the bonding material on one or both of the pad and the pad structure of the microelectronic component 10 forms an electrical connection between the pad structure and the respective pad. Steps to the body,
-Curing the conductive adhesive between the pad and the pad structure and bonding the microelectronic component with a shear strength greater than 1 Mpa;
including.

In an embodiment, a connection arranged to interconnect a microelectronic component having one or more electrical connection pads, in particular a bare die component 10, to the microelectronic component via each one or more connection pads. A method of bonding on a substrate 20 having a pad structure 40 on a substrate surface is provided, the method comprising:
Providing a donor film comprising a solder paste 151 and a dynamic release layer 152;
-Aligning the laser beam of the laser system and guiding the donor film at a distance from the substrate surface;
A laser beam on the dynamic emission layer such that the active emission layer is activated and the solder paste 50 transferred from the donor film covers a selected portion of the connection pad or connection pad structure. The laser beam is timed and energy limited such that the transferred solder paste includes a flux comprising a volume percent flux greater than 10%; and
The pad of the microelectronic component 10 is placed on the pad so that the solder paste on one or both of the pad and the pad structure of the microelectronic component 10 forms an electrical connection between the pad structure and the respective pad. A step addressing the structure;
Reflowing the solder paste between the pad and the pad structure to bond the microelectronic component with a shear strength greater than 1 Mpa;
including.

  In contrast to prior art methods, these embodiments share the common concept of providing high speed, high resolution bonding of the components after the pads of the microelectronic components are placed on the respective pad structures of the substrate. Have The transferred adhesives or solder pastes each remain in their original state, in particular the bonding properties are optimal as they remain curable or reflowable during the transfer process, ie prior to placement. , After placing the component 10 on the pad structure, the bonding material, specifically adhesive or solder paste, can be cured or reflowed respectively, with electrical connectivity that can have a bonding strength of more than 1 Mpa Robust bonding is provided. This is a very efficient and cost effective method for mass production industrial applications.

In this setup, a laser spot formed with a spot size D of about 20-200 microns, specifically Nd with a fluence of 20-300 mJ / cm ² , more specifically 40-150 mJ / cm ^2. : YAG or Excimer laser spots are used.

This spot is aimed on a transparent carrier substrate 70, in this example 248 nm KrF excimer and quartz glass for PET, or soda lime glass for 355 nm Nd: YAG laser. A conductive die attach die bonding material 15 is provided on a substrate 70, which includes a die bonding material layer 151 of the conductive thermosetting material or flux base solder paste, and a conductive thermosetting or flux base. And a dynamic release layer 152 adjacent to the die bonding material layer 151 of solder material. Dynamic release layers are well known in the art and typically include a composition formed in the layer that, when locally irradiated, abruptly transforms into a gaseous material, Dynamic release is provided by the propellant action of the particulate material. In this example, the dynamic emission layer 152 is formed of a triazine layer having a thickness of about 100 nm, and the layer functions as a sacrificial dynamic emission layer (DRL) when photoactivated. Contains a polymer that decomposes into nitrogen and other organic volatile gases 1521. If it can provide dynamic release, i.e., dynamic release of a curable conductive adhesive or flux-based solder paste bonding material from the dynamic release layer 152 to selected portions of the connection pad structure 40, It is equally appropriate to provide the dynamic release layer 152 with materials of other compositions. The typical peak absorption has been found to be at 290-330 nm, the ablation threshold at 308-248 nm is very low, 22-32 mJ / cm ^2, and the donor die attach film layer or solder paste has a thermal No load is applied, and the die bonding material 1511 remains in a thermosetting state in the original state after transfer. For example, the laser beam may cause the bonding material transferred to a selected portion of the connection pad or connection pad structure 40 to be curable by dynamic emission from the dynamic emission layer 152, or 10%. Timing and energy may be limited to consist of greater volume percent solder flux. Thus, during transfer from the dynamic emission layer 152 to the pad structure by applying a laser beam onto the dynamic emission layer 152 adjacent to the conductive thermosetting material of the die bonding material layer 15. Desirable material properties can be maintained, thereby activating the dynamic release layer 152 to move the conductive die attach die bonding material 1511 and transfer selected portions of the substrate 20 to the conductive die. • Covered with bonding material.

  Covering selected portions with a conductive die bonding material, of course, has the function of providing an appropriate electrical connection between the pad structure and the conductive die. As can be seen in FIGS. 2a and 2b, in this example, as commercially available from Henkel as CE3103WLV, for example typically 4-10E-4 ohms. electrical conductivity on a Cu-coated substrate or silver track with a volume resistivity of cm, a typical curing temperature of 120 to 150 ° C. for 10 to 3 minutes, and 15 to 25 Pa. A thermosetting isotropic conductive adhesive material 151 having a viscosity of s is transferred. To illustrate the general applicability of the method, 160-180 Pa. Another experimental conductive adhesive from Henkel, consisting of a high viscosity conductive adhesive with a viscosity of s, is transferred and cured at 150 ° C. for about 10 minutes. The conductive adhesive 151 is provided on the dynamic release layer 152 and is provided as a homogeneous layer having a thickness of 20 to 30 microns, specifically 25 microns. This thickness is controlled to about 25 um or 50 um, but could theoretically be any thickness. The donor bonding material is held at a distance of about 13 to 150 microns from the substrate by shim 80.

  Furthermore, it is also possible to replace the conductive adhesive with a flux base Sn96.5Ag3Cu0.5 type 5 solder paste. Proper transfer of solder with flux can be achieved and functionality can be ensured by reflow. Also, non-conductive structural adhesives or pressure sensitive adhesives can be successfully transferred. The adhesive is 1.2 Pa.s. The viscosity may be s.

  In some embodiments, the die bonding material layer is about 7E-4 ohms. It can be a 15-30 micron thick solid thermoplastic layer having a high conductivity of cm and curing conditions of about 1.5 hours at 175-200 ° C.

  FIGS. 3A and 3B show a transfer system for transferring a conductive thermosetting adhesive or solder paste from tape 70 that is wound on reel 185 and back to reel 180. The bonding method disclosed herein is an accurate and flexible combination with an alignment detection system that makes the method suitable for placement in a flexible foil where web integrity is not normally guaranteed. It can adapt to the correction and make this possible. In FIG. 3A, the tape 70 can be made from a PET foil, aligned through the donor supply system 75 under the beam of the laser 195 and transferred to the pad structure 40 of the receiving substrate 20. The substrate can be moved by a motorized stage 190 that can be moved according to alignment control means for aligning the substrate 20 with respect to the laser 195. FIG. 3B shows another example, in which the donor film 15 is moved by a motorized stage 220 having respective guides 210 and 215 for guiding the film on the substrate 20 in an XY manner. The substrate can be moved in the moving direction P by the stage 220. The laser 195 can be moved mechanically or optically so that the transfer of the bonding material 1511 can be aligned with the substrate 20.

  FIG. 4 shows a schematic assembly process for the microelectronic component 10 including transferring the chip bonding and interconnect material by LIFT technique in the transfer section 250 as indicated above. Specifically, a bare chip component interconnect method for interconnecting and bonding a bare chip component 10 onto a flexible substrate or foil 20 having a conductive die attach material 50 and a non-conductive die attach material 60 Is disclosed. The method prepares a flexible substrate 20 having a contact portion 40 and a bare chip component 10 with a contact portion 30 to be placed on a position predefined by positioning means 255. Steps. The method may cure the conductive thermoset 280 and optionally the thermoset non-conductive adhesive 285 or reflow the solder melt 280 before the foil, which is a flexible substrate, is rewound onto the reel 270. A thermal exposure step 260 that permanently secures the chip.

In the disclosed reel-to-reel method of FIG. 4, the substrate 20 or carrier web is unwound from the first reel 265 and guided to the second reel 270 via a set of guide rollers 240; It is wound up. In the unwrapped state, various sub-processes can be executed. Specifically, as one of these sub-processes, the bonding of bare chip components already disclosed in the previous FIG. 1 and FIG. 2 is executed. The Specifically, these sub-processes include
Creating the interconnect 250 by a LIFT transfer process that moves the conductive and non-conductive die bonding material 60 to the receiving side;
A bare chip component 10, such as a silicon-based bare chip component or LED 10, is supplied by the pick and place unit 255 over the interconnect material in the target area on the substrate 20 and the pressure To control,
Fixing the die chip part 10 by thermal curing of the conductive and non-conductive adhesive 60 and / or reflow of the solder paste by the thermosetting unit 260;
Can be included.

  The chip 10 can be permanently fixed in place on the substrate by, for example, a bonding tool 260 such as a heater that activates the thermosetting material in the electrically conductive die bonding donor material, The donor material is thermoset in a cure temperature range that is elevated from the temperature of the LIFT operation at 260 so that the component can be thermoset or any other known for attaching the chip to a (flexible) substrate. It is fixed by the method.

  In the exemplary configuration shown in FIG. 5, the bump array consists of bumps 40 on the substrate 20, typically having a diameter in the range of 10-500 microns. This density is desirably a density such that a sufficient number of bumps 30 exist under the chip 10 to be arranged. For example, if the side length of the chip is 1 mm, a distance of 200 microns is sufficient, for example. (5 bumps x 5 bumps under the chip). The bumps of solder paste or thermosetting adhesive 50 can be placed on the bonding pads or on the pads of the substrate, and then the bump array 30 on the chip 10 is placed on the substrate by, for example, flip chip method. Can be placed and bonded. In addition to the above, the structural adhesive 60 may be transferred for further structural bonding.

  In the example of FIG. 6, for example, passive components 310 such as resistors, capacitors, or inductors, or additional microelectronic components such as bare die LEDs 410 can be placed on the patterned foil 20 and conductive adhesive An agent or solder paste 50 and a non-conductive adhesive 60 are applied by the techniques described above. Both resistor 310 or bare die LED 410 will in this example be connected to conductive track 40 of substrate foil 20 via conductive bumps. In particular, such circuits are advantageously applied to flexible substrates, for example where silver or copper tracks on PEN or PET foil are used. Typical chip height can vary, for example, between 0 and 250 micrometers. Bare die LED 410 has anode bumps 425 and cathode bumps 426 that are about 80 × 80 microns to as small as about 50 × 50 microns, and a junction area 415 (LED portion) of about 230 × 190 microns.

  While the invention has been shown and described in detail in the drawings and foregoing description, such presentation and description are to be considered illustrative or exemplary and not restrictive, and the invention shall not It is not limited to the disclosed embodiments. In particular, unless otherwise apparent from the context, aspects of the various embodiments dealt with in the individually described various embodiments are also disclosed for any associated physically possible variations. The scope of the present invention extends to such combinations. Furthermore, the step of depositing either conductive or non-conductive adhesive can be performed as one embodiment of a method of handling chip die bumps in the chip manufacturing process. The method includes clamping a wafer having specific bumps provided with a conductive adhesive; providing a conductive die attach donor film while maintaining a distance from the top surface of the wafer; Aligning the laser beam of the system and corresponding to a particular bump on the wafer to direct a conductive die attach donor film, the conductive die attach donor film facing the wafer Applying a laser beam on the side opposite to the side that is facing; adjusting the timing, energy, and direction of the laser beam to move it toward the bump to be handled of the conductive die-attached donor film material And a step to be performed.

  Further embodiments include a multi-shot process, in which a new conductive die attach donor film is guided to correspond to the bumps and a laser beam is applied on the conductive die attach donor film. An iterative step is provided that moves the particles of the conductive die bonding material onto the bumps.

  In order to achieve cost effective interconnection at a rate of at least 1000-3000 bumps per second, the repetition rate of the laser is desirably at least 60-600 kHz. In order to replenish conductive die attach donor film at such rates, a conductive die attach donor film replenishment module with high replenishment rate capability, eg, conductivity greater than 0.1 m / s for bumps. Modules having a replenishment rate of die attach donor film are highly advantageous. This high laser repetition rate combined with a relatively large number of bumps of about 60-200 is competitive for stencil or screen printing, much more than the deposition rate of applications with jet printing of about 10 bumps per second Provides an effective operating area for this chip bonding application.

  FIG. 7 shows an example of a structured donor film 70. To enhance the formation of well-defined bonding materials, the donor film includes a pre-processed form, for example, a sacrificial layer provided in a matrix 15 of sacrificial material, a patterned conductive die bonding material layer Can be supplied in form. A suitable thickness of the homogeneous layer can be distributed between 50 and 2000 nm, desirably in the range of 50 to 500 nm, more desirably in the range of 50 to 250 nm.

  Alternatively, some embodiments of bump handling can be implemented by stepping, ie, a non-roll-to-roll process. For example, high-speed beam modulators (such as galvano mirrors, polygon mirrors, acousto-optic or electro-optic modulators) provide scanning motion in the first direction of the laser beam. The modulator can be controlled by a feed-forward process, where the bump coordinates are provided from an external source with chip die layout data. Alternatively, the modulator can be used as a scanning unit that maps bump coordinates in the pre-scan stage. Alternatively, additional optical feedback systems can provide laser alignment with respect to the bumps. Optionally, the main beam is divided into about 2 to 20 sub-beams, and in this embodiment, a new conductive die attach die bonding material is directed to correspond to the bumps to generate a donor material. Each single bump may be processed by a multi-shot process in which repeated steps are provided.

Those skilled in the art will appreciate other variations of the disclosed embodiments from a study of the drawings, the disclosure, and the appended claims in practicing the claimed subject matter. In the claims, the term “comprising” does not exclude other elements or steps, and the indefinite article “a” or “an” does not exclude a plurality. A single unit may fulfill the functions of several items recited in the claims. The mere fact that certain measures are recited in different dependent claims does not indicate that a combination of these measured cannot be used to advantage. Any reference signs in the claims should not be construed as limiting the scope. The advantage of the disclosed laser transfer process over conventional printing is that stencil printing techniques (typically 75 μm resolution spot size) are generally not achievable, and even more so with jet printing (typical resolution spot size: 200 μm). Use for regions of features where <50 μm resolution is intended, which cannot be achieved. Furthermore, the donor material can have a wide range of viscosities (1 Pa.s to 160 Pa.s (not exhaustive)) that can be transferred. Typical viscosities for stencil printing are> 50 Pa.s. s and a typical viscosity for ink jet printing is <0.1 Pa.s. s. In contrast to stencil printing and screen printing, this method is a non-contact direct drawing method with the potential for on-the-fly correction using an imaging system for web deformation.

Claims (14)

A connection pad structure arranged to interconnect a microelectronic component having one or more electrical connection pads, in particular a bare die component (10), to the microelectronic component via one or more connection pads, respectively. Bonding onto a substrate (20) having (40) on the substrate surface, the method comprising:
Providing a donor film comprising a curable conductive adhesive or flux base solder paste bonding material (151) and a dynamic release layer (152) adjacent to said bonding material layer;
Aligning the laser beam of the laser system and directing the donor film at a distance from the substrate surface;
The dynamic emission layer is activated such that a selected portion of the connection pad or the connection pad structure is covered by a bonding substance (50) transferred from the bonding material layer; Applying the laser beam on a layer;
The microelectronic component such that the bonding material on one or both of the pad and the pad structure of the microelectronic component (10) forms an electrical connection between the pad structure and the respective pad; Assigning the pad of (10) to the pad structure;
Bonding the microelectronic component with a shear strength greater than 1 Mpa by curing the conductive adhesive of the bonding material or reflowing the solder paste;
Including a method.   The method of claim 1, wherein the bonding material is thermoplastic in an operating temperature range and is thermoset in a curing temperature range that is elevated from the operating temperature.   A method according to any preceding claim, wherein the working temperature ranges from 10 degrees Celsius to 180 degrees Celsius.   A method according to any preceding claim, wherein the substrate is a flexible substrate (20) having a radius of curvature of at least 1 cm.   A method according to any preceding claim, wherein the distance to the surface of the die is kept in the range of 1 to 200 microns.   The method according to any of the preceding claims, wherein the die bonding material layer has a thickness in the range between 10 and 50 microns.   A method according to any preceding claim, wherein the donor film is prepared with pre-processed patterning.   The method of claim 7, wherein the pre-processed patterning forms a grid having a grid size that is less than or equal to the laser spot size.   The method of claim 8, wherein the patterning has a grid pitch in the range of 40-80 microns.   The method according to the preceding claim, wherein the connection pads are smaller than 80 micrometers.   The bonding material is a thermosetting resin that is viscous in a working temperature range, and the viscosity is 1 to 160 Pa.s. A method according to the preceding claim, in the range between s.   The laser beam timing and energy are limited so that the transferred bonding material is kept curable or consists of a volume percent solder flux greater than 10%. the method of. A connection pad structure arranged to interconnect a microelectronic component having one or more electrical connection pads, in particular a bare die component (10), to the microelectronic component via one or more connection pads, respectively. Bonding onto a substrate (20) having (40) on the substrate surface, the method comprising:
Providing a donor film comprising a curable conductive adhesive (151) and a dynamic release layer (152);
Aligning the laser beam of the laser system and directing the donor film at a distance from the substrate surface;
The dynamic release layer is activated so that selected portions of the connection pads or the connection pad structures are covered by an adhesive (50) transferred from the donor film; Applying the laser beam on a layer, wherein the laser beam is limited in timing and energy such that the transferred adhesive remains curable;
The microelectronic component such that the bonding material on one or both of the pad and the pad structure of the microelectronic component (10) forms an electrical connection between the pad structure and the respective pad; Assigning the pad of (10) to the pad structure;
-Curing the conductive adhesive between the pad and the pad structure and bonding the microelectronic component with a shear strength greater than 1 Mpa;
Including a method. A connection pad structure arranged to interconnect a microelectronic component having one or more electrical connection pads, in particular a bare die component (10), to the microelectronic component via one or more connection pads, respectively. Bonding onto a substrate (20) having (40) on the substrate surface, the method comprising:
Providing a donor film comprising a solder paste (151) and a dynamic release layer (152);
Aligning the laser beam of the laser system and directing the donor film at a distance from the substrate surface;
The dynamic release layer is activated so that the solder pad (50) transferred from the donor film covers the selected portion of the connection pad or the connection pad structure. Applying the laser beam on an emissive layer, wherein the laser beam is timed and energyd such that the transferred solder paste includes a flux comprising a volume percent flux greater than 10%. The acting step being limited;
The microelectronic component such that the solder paste on one or both of the pad of the microelectronic component (10) and the pad structure forms an electrical connection between the pad structure and the respective pad; Assigning the pad of the component (10) to the pad structure;
Reflowing the solder paste between the pad and the pad structure to bond the microelectronic component with a shear strength greater than 1 Mpa;
Including a method.